1. Field of the Invention
The present invention relates to a dock leveler for ramp-bridging apparatus that includes a bridge plate, the dock-end of which is pivotably mounted about a horizontal axis, and an extensible and retractable extension that is disposed at the free end of the bridge plate and that serves for placement and support on a platform that is to be loaded or unloaded. The dock leveler also has a switch that effects or permits an automatic return into the rest position of the dock leveler.
2. Description of the Priot Art
Difficulties arise with such dock levelers if the vehicle that is to be loaded or unloaded is still in the dock region, but for some reason is no longer in connection with the extension of the bridge plate, i.e. no longer contacts the latter. This can occur, for example, when the bridge plate has already assumed its lower end position, where it rests against an abutment, but at the same time the platform of the vehicle has sunk even further, perhaps because a load-carrying device has been driven thereon. Under these conditions, a gap is formed between the extension and the platform. As a result, accidents can occur, especially since the dock leveler can then retract into the neutral position.
An object of the present invention is to improve dock levelers of the aforementioned general type in such a way that an undesired retraction into the so-called neutral position cannot occur even when a gap exists between the extension and the platform.